Improvement in balanced slide-valves



Patented Oct. l0, 1871.

'Improvement in Balance Slide Valves.

Jaya

1 C. H. HUTCHINSON'.

No. ll9,769.

@umm @ttnmgf' y UNITED STATES FFGE' IMPROVEMENT IN BALANCED SLIDE-VALVES.

Specification forming part of Letters PatentvNo. 119,79, dated October 10, 1871.

To all whom it may concern:

Be it known that I, CHARLEs H. HUTCHIN- SON, of Concord, in the county of Merrimack and State of New Hampshire, have invented a new and Improved Balanced Slide-Valve5 and I do hereby declare that the following is afull, clear, and exact description thereof, which will enable others skilled in the art to make and use the same, reference being had to the accompanying drawing forming part of this specification.

My invention consists in the improvement of slide-valves, as hereinafter fully described and subsequently pointed out in the claim.

Figure l is a longitudinal sectional elevation of improved balanced-valve arrangement as applied when the valve and balancing devices are to reciprocate together. Fig. 2 is a plan of Fig. l. Fig. 3 is a section of the plate employed for counteracting the warping and springing of the top of the valve-chest. Fig. 4 is a section, showing the arrangement when the balancing devices do not reciprocate with the valve. Fig. 5 isa plan view of Fig. 4. Fig. 6 is a section, showing the manner in which a spring may be used for connecting the balancing-plates instead of the cylinder-and-piston arrangement, and for use in connection with steam-pressure for maintaining steam-tight bearings at the top and bottom of the steam-chest, while limiting the down-pressure of the valve. Fig. 7 is a plan View of the bottom of the upper plate and its cylinder.

Similar letters of reference indicate correspond ing parts.

A is the top of the steam-chest, and B the bottom or valve-seat. C represents the live-steam ports, and D the common exhaust-port. This may be used with my improved valve when not exhausting' through the top, but is not needed when so exhausting, which I propose to do as a general thing. E is a vertical cylinder, which in one arrangement may be the valve also, and slide on the valve-seat, as indicated in Fig. l; or, it being stationary, may rest on a valve, F, sliding under it, as in Fig. 4. G is another cylinder iitting into cylinder E, with its face bearing against the under side of the plate H, attached to the under side of the top A of the steam-chest, and provided with ordinary piston-packing I in the part working within cylinder E, to be forced out against the wall of cylinder E by steam let in behind it through a passage, K; -or it may be any approved packing. Both of these cylinders have a rectangular plate or flange at the end tting against the wall of the steam-chest, as indicated in Figs. 2 and 5, L being the iiange of cylinder E and M the llange of cylinder G. The steampressure on these anges is the measure of the force with which they are coniined to the seats, and the action is governed thereby, except in the case of the lower cylinder, which also receives `pressure on its upper end at M. The balance of the area of the valve is not subject to pressure, by reason of the steam being excluded from it by the cylinder G and its plate. The pressure of the valve on the valve-seat may therefore be fixed at any given amount by the size of the iiange. I propose to make these cylinders hollow, and to provide an opening', N, through the top of the valve-chest for exhausting thereat, and when so arranged the port D will not be required 5 but, instead, an opening will be made directly up through the valve-cylin ders and steam-chest. As the top of the steam-chest is liable to spring upward by an action of the steam, and in such case becomes so warped or cramped that a steam-tight joint cannot be maintained between the face of cylinder G and it, I propose to introduce a plate, H, between them, with a broad face at the under side for said cylinder to work against, and a contracted central upper face to form the point of connection with the steam-chest top and its center, which allows it to rise and fall with the steamchest top without warping.

I have found, in practice, that where the area of the upper surface of the iiange or face of cylinder G, working against the upper wall of the steam-chest, is about equal to the area of the under side subject to steam-pressure, the cylinder is liable to dance or vibrate rapidly by the steam working between it and the steam-chest, or itV may be from other causes; but, whatever the cause may be, I have found a sure remedy therefor in reducing the area of the surface of the upper part bearing on the top of the steam-chest, and this I propose to do by making the cavities P therein, which cavities I connect by channels Q, and provide these channels. with one or more passages, It, always open to the exhaust to maintain a vacuum in said cavities.

In case the valve F is used the said cylinders will not reciprocate, but will be secured to the top A of the valve-chest by bolts S and a disk,

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The combination, with shield H, of the cylinder G having a square ange, M, and working directly against the under side thereof, as and for the purposes specified.

2. The arrangement of fixed cylinders E G and slide-valve F in a steam-chest, when all are constructed as shown in Fig. 4 of drawing, and for the purpose specified.

CHARLES H. HUTOHINSON.

Witnesses GHAs. G. LUND,

L. D. STEVENS. (152) 

